Providing World-Class Treatment Using Cutting-Edge Technology

Our physicians provide patients with world-class treatment using cutting-edge technology at our many locations throughout New England.

Radiation Oncology Associates is Proud to Serve New England

Founded in 1971, Radiation Oncology Associates has been serving the needs of cancer patients in New Hampshire, Maine and Massachusetts for over 45 years. One of New England’s oldest and largest practices in radiation oncology, we strive to provide our patients with the freedom to receive the best cancer care close to home. We individualize treatment with compassion and cutting-edge technology to ensure you get the support and medical care that you need.

External beam radiation therapy, or teletherapy, involves a linear accelerator machine used to generate and direct high-energy X-rays as a treatment. This is the most common category of radiation treatment.

External Beam Radiation Therapy

External beam radiation therapy, or teletherapy, involves a linear accelerator machine used to generate and direct high-energy X-rays as a treatment. This is the most common category of radiation treatment.

Systemic Radiation Therapy

About Us

Serving the Needs of Patients in New England for Decades

Radiation Oncology Associates (ROA) is composed of highly trained, board certified Radiation Oncologists with extensive and up-to-date clinical expertise in the compassionate delivery of cancer care. We are fortunate to be have physicians with all levels of experience and clinical interests from those having recently completed training, to our more senior partners with more than 20 years in clinic. The unique size and diversity of our group allows us to deliver exceptional patient care across many sites, translating into better treatment options closer to home for many of our patients.

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Meet Our Doctors

Jeffrey Brower

MD, PhD

Jeffrey Brower received his Bachelor of Science degree in Microbiology and Cell Science with a minor in Chemistry from the University of Florida. He then went on to earn his Ph.D. in Molecular Biology, during which time his research led to the discovery of a novel gene responsible for cellular respiration and energy metabolism. During his Ph.D. research, he was awarded the Alumni Fellowship and other research awards to include the Medical Guild award for his work in molecular biology. Following the completion of his Ph.D., Dr. Brower matriculated to medical school at the University of Florida, graduating with research honors in 2012.

Ping Zhou

MD, PhD

Dr. Zhou received her Bachelor of Science degree in Biology from Beijing University and then went to New York, earning a Ph.D. degree in cancer research from Columbia University in 1996. During her Ph.D. research, she studied the molecular mechanisms of cancer and was awarded Fellowships from American Cancer Society and National Foundation for Cancer Research.

Dr. Zhou graduated from Harvard Medical School, cum laude, in 2001. During medical school, she pursued her interest in cancer research at MIT and Dana Farber Cancer Institute, where she won an excellent MD thesis award.

H. Andy Singh

MD

Andy Singh received his Bachelor of Science degree in genetics from the University of California, Berkeley, in 1991 with honors. In 1995, he received his medical degree from University of Chicago Pritzker School of Medicine.

Dr. Singh completed an internship in internal medicine at Mount Auburn Hospital in Cambridge, MA. He continued his training in radiation oncology at Memorial Sloan-Kettering Cancer Center, where he was named Chief Resident for 1999-2000. During residency, Dr. Singh developed expertise in three dimensional (3D) conformal radiation therapy, intensity modulated radiation therapy (IMRT) and brachytherapy.

Thomas A. Sheldon

MD

Dr. Sheldon received his Bachelor of Science degree in biochemistry from the University of Wisconsin at Madison in 1976 where he was a member of the Phi Beta Kappa honors society. While in college, he worked with a research team studying interferon. He graduated from Tufts University School of Medicine in 1980. During medical school, he participated in research in radiobiology at the Harvard School of Public Health.

Dr. Sheldon completed an internship in medicine and surgery at Newton-Wellesley Hospital in Massachusetts, where he received the Margaret Derby Scholarship award in 1981.

Bryan Rowe

MD

Bryan Rowe studied biology at Wesleyan University and received his Bachelor of Arts with honors in 2000. He graduated from the University of Connecticut School of Medicine in 2007 with the Excellence in Medical Studies award.

Dr. Rowe trained in radiation oncology at Yale New Haven Hospital, where he served as chief resident from 2011 to 2012. He gained extensive experience in the most current radiation therapy techniques, including intensity modulated radiotherapy (IMRT), image-guided radiotherapy (IGRT), stereotactic radiotherapy, and brachytherapy.

Vivek Patel

MD, PhD

Vivek Patel received his Bachelor of Science degree from Cornell University in 2006, where he was awarded honors Magna Cum Laude with Distinction in research. He further pursued his interest in biomedical science at the Weill Medical College of Cornell University, where he investigated novel drug therapies for blood disorders. He earned his M.D. and Ph.D. degrees from the Albert Einstein College of Medicine in 2007, where he achieved grant funding from the National Institutes of Health (NIH) and American Medical Association (AMA) for his work on RNA biology. Dr. Patel was elected to the Alpha Omega Alpha honor society upon his graduation from medical school in 2013.

Etin-Osa Osa

MD

Etin-Osa Osa received her Bachelor of Science degree in Biology and Chemistry with highest academic distinction from Howard University in 2005 and earned her medical degree from New York University School of Medicine in 2009.

Dr. Osa went on to complete her internship in General Medicine and residency in Radiation Oncology at New York University (NYU) from 2009 to 2014.

Klaudia Hunter

MD

Klaudia Hunter received Bachelor Degrees with Distinction in both philosophy and biology from the University of Illinois at Chicago in 2001. She then graduated with honors from the University of Illinois Medical School in 2006 after completing the James Scholar Program for Independent Study and playing a leadership role in the Alpha Omega Honors Society.

Dr. Hunter completed her surgical internship at the University of California at San Diego in 2007. She continued in the neurosurgical residency training program at the University of California at San Diego until June 2009 when she chose to leave to pursue a career in radiation oncology.

William O’Meara

MD

Bill O’Meara received his Bachelor of Arts in English from the University of Notre Dame in 1992 and completed medical training at Tulane University School of Medicine in 1997. While in medical school, he simultaneously obtained a masters degree in public health.

Dr. O’Meara completed an internship in internal medicine in 1998 at the Naval Medical Center in San Diego. From 1998-2002, he served as an active duty Naval medical officer with operational forces.

Asa J. Nixon

MD, MPH

Asa Nixon received his Bachelor of Arts degree from Dartmouth College in 1984. In 1988, he graduated with his medical degree from New York University School of Medicine.

Dr. Nixon completed two years of residency in general surgery at New England Deaconess Hospital in Boston, MA. He continued his training in radiation oncology at the Joint Center for Radiation Therapy (JCRT), Harvard Medical School. During residency, Dr. Nixon completed a fellowship in cancer epidemiology from the Harvard School of Public Health, receiving a Masters in Public Health degree.

Su Metcalfe

MD, MPH

Su Metcalfe received her Bachelor of Arts in Asian Studies from Pomona College in 1996. Following this, she received a Masters of Science in Biology with a focus in Immunology from NYU in 1999 and completed a research fellowship at the National Institutes of Health. She earned a Masters of Public Health degree from Columbia University in 2001. In 2005, she graduated from the University of Vermont College of Medicine.

Christopher Freese

MD

Chris Freese obtained his BBA in Management and Strategic Leadership from Ohio University. After completing his undergraduate studies, he decided to pursue a career in medicine and began working as a research assistant at the Cincinnati Children’s Hospital Medical Center studying the pathogenesis of pulmonary fibrosis. He then matriculated into medical school at the University of Cincinnati College of Medicine where he graduated top of his class and was elected into the Alpha Omega Alpha Honors Society.

Andrea B. McKee

MD

Andrea McKee received her Bachelor of Arts degree in biology in 1992 from the University of Pennsylvania with honors. She graduated from Columbia University College of Physicians and Surgeons in 1996. During college and medical school, she participated in laboratory and clinical research prior to continuing with her clinical training.

She continued her training in radiation oncology at Memorial Sloan-Kettering Cancer Center, where she was named Chief Resident for 2000-2001.

Arul Mahadevan

MD

Arul Mahadevan received his Bachelor of Medicine and Surgery from the University of Madras (Chennai) in 1987 and his Master of Surgery in Orthopedics from the University of Bombay in 1991.

Since joining Radiation Oncology Associates in 2008, Dr. Mahadevan has helped us make new radiation technologies available. He remain active in clinical trials with RTOG and serves on the Government Relations Committee and Education Committee for the American Society of Radiation Oncology. He is also the Medical Director of the Radiation Therapy Training Program of the New Hampshire Technical Institute.

Jeffrey Lemons

MD, MS

Jeff Lemons earned his Bachelor of Science degree from the University of Michigan in Ann Arbor, MI with a major in Cellular, Molecular, and Developmental Biology and a minor in Spanish. After finishing at Michigan, he matriculated into medical school at Temple University School of Medicine in Philadelphia, PA and graduated in 2013 as a member of the Alpha Omega Alpha Honor Society.

After medical school, Dr. Lemons completed internship at Crozer Chester Medical Center in Upland, PA followed by radiation oncology residency at the University of Chicago where he served as Chief Resident in his final year.

Brian R. Knab

MD

Brian Knab received a Bachelor of Arts degree in interdisciplinary studies at the University of Virginia in 1997. He graduated from Duke University Medical School in 2002 as a member of the Alpha Omega Alpha medical honor society. While in medical school, he participated in a year-long laboratory research program at the University of California at San Francisco investigating new cancer treatments.

Following medical school, Dr. Knab returned to the University of Virginia to complete an internship in internal medicine.

Matthew S. Katz

MD

Matt Katz received his Bachelor of Arts degree in history from Northwestern University in 1992 and graduated from the University of Massachusetts Medical School in 1998. During medical school, he also completed a fellowship in pathology.

Dr. Katz completed his radiation oncology residency at Memorial Sloan-Kettering Cancer Center in 2003. He developed expertise in the use of newer technologies such as intensity modulated radiation therapy (IMRT) to improve the accuracy and safety of radiation therapy. From 2003-2004, Dr. Katz was on staff at the Massachusetts General Hospital in the Department of Radiation Oncology.

Howard Hsu

MD

Howard Hsu received his Bachelor of Science degree in Bioengineering from the University of California Berkeley in 1998. He served as a Peace Corps Volunteer in a rural village of South Africa from 1999-2001, working on education and community health projects. He earned his medical degree from Cornell University Medical College in 2005.

Dr. Hsu served for three years as an intern and resident in General Surgery at Washington University / Barnes-Jewish Hospital from 2005-2008. He subsequently pursued research training in radiation biology at the University of California San Francisco / Lawrence Berkeley National Laboratory.

Stephen Harris

MD

Stephen Harris graduated with distinction with a degree in biomedical engineering from Purdue University in 2001. He went on to Indiana University School of Medicine in 2005 where he was a member of the Alpha Omega Alpha medical honor society. Dr. Harris stayed in Indianapolis to complete his internship at Indiana University before moving to the University of North Carolina to complete his residency in radiation oncology. While at UNC, Dr. Harris served as chief resident from 2008-2010.

Christopher Freese

MD

Andrea B. McKee

MD

Arul Mahadevan

MD

Jeffrey Lemons

MD, MS

Brian R. Knab

MD

Matthew S. Katz

MD

Howard Hsu

MD

Stephen Harris

MD

Latest News

Radiation Oncology Associates would like to congratulate Dr. Brian Knab, Dr. Su Metcalfe, Dr. Tom Sheldon, Dr. Andrea McKee, and Dr. Asa J. Nixon for being selected for the distinguished honor of "top doctors" for 2019. This distinction is bestowed upon those doctors who have bee...

UF College of Medicine Alumni Jeffrey Brower, Ph.D. ’08, M.D. ’12, recently received the University of Florida's 40 under 40 designation and an Outstanding Young Alumni award. Read a short excerpt of UF's article below....

UF College of Medicine Alumni Jeffrey Brower, Ph.D. ’08, M.D. ’12, recently received the University of Florida's 40 under 40 designation and an Outstanding Young Alumni award. Read a short excerpt of ...

UF College of Medicine Alumni Jeffrey Brower, Ph.D. ’08, M.D. ’12, recently received the University of Florida's 40 under 40 designation and an Outstanding Young Alumni award. Read a short excerpt of ...

Christopher Freese, MD

Peabody, Burlington | Radiation Treatment & Oncology

Burlington

Peabody

Chris Freese obtained his Bachelor of Business Administration in Management and Strategic Leadership from Ohio University. After completing his undergraduate studies, he decided to pursue a career in medicine and began working as a research assistant at the Cincinnati Children’s Hospital Medical Center studying the pathogenesis of pulmonary fibrosis. He then matriculated into medical school at the University of Cincinnati College of Medicine where he graduated top of his class and was elected into the Alpha Omega Alpha Honors Society.

After completing his preliminary medicine year at The Christ Hospital in Cincinnati, he pursued his training in radiation oncology at the University of Cincinnati Medical Center, serving as chief resident from 2018 to 2019. During his residency, he obtained extensive experience in modern radiotherapy techniques including intensity modulated radiotherapy (IMRT), stereotactic radiotherapy, and proton therapy. In addition to this clinical experience, he participated in numerous research projects, publishing multiple manuscripts and presenting at various meetings including Yokohama, Japan at the Particle Therapy Co-Operative Group meeting for which he received the Travel Fellowship Award to present his work. Outside of research, Dr. Freese sought leadership roles within the radiation oncology community. Dr. Freese was the co-chair of the Global Health Subcommittee for the Association of Residents in Radiation Oncology (ARRO). He was also elected nationally to be a member of the ARRO Executive Committee. Lastly, he completed an externship at The Christie NHS Foundation Trust in Manchester, England to learn new techniques for providing quality care.

Dr. Freese joined Radiation Oncology Associates in 2019 after completing his training. He enjoys developing lasting patient relationships and providing compassionate, effective care to all. Outside of work, Dr. Freese enjoys spending time with his family and traveling.

Ping Zhou, MD, PhD

Londonderry, Nashua | Radiation Treatment & Oncology

View Dr. Zhou’s Publications Below

Londonderry

Nashua

Dr. Zhou received her Bachelor of Science degree in Biology from Beijing University and then went to New York, earning a Ph.D. degree in cancer research from Columbia University in 1996. During her Ph.D. research, she studied the molecular mechanisms of cancer and was awarded Fellowships from American Cancer Society and National Foundation for Cancer Research.

Dr. Zhou graduated from Harvard Medical School, cum laude, in 2001. During medical school, she pursued her interest in cancer research at MIT and Dana Farber Cancer Institute, where she won an excellent MD thesis award.

After completing an internship in Medicine at Carney Hospital in Massachusetts, she trained in residency at the Joint Center for Radiation Therapy at Harvard Medical School from 2002 to 2006. During her residency, Dr. Zhou conducted and published clinical research in breast, lymphoma, and prostate cancer, and she trained in the use of latest technologies such as intensity modulated radiation therapy (IMRT), stereotactic radiosurgery and stereotactic radiation therapy.

Dr. Zhou joined Radiation Oncology Associates in 2006 after completing her training. I find it most rewarding in helping cancer patients and their families in the fight against cancer. I feel privileged to share my knowledge and expertise in cancer treatment with my patients here in New Hampshire.

H. Andy Singh, MD

Dover, Portsmouth | Radiation Treatment & Oncology

Dover

Portsmouth

Andy Singh received his Bachelor of Science degree in genetics from the University of California, Berkeley, in 1991 with honors. In 1995, he received his medical degree from University of Chicago Pritzker School of Medicine. During medical school, he was active in research for which he won several awards.

Dr. Singh completed an internship in internal medicine at Mount Auburn Hospital in Cambridge, MA. He continued his training in radiation oncology at Memorial Sloan-Kettering Cancer Center, where he was named Chief Resident for 1999-2000. During residency, Dr. Singh developed expertise in three dimensional (3D) conformal radiation therapy, intensity modulated radiation therapy (IMRT) and brachytherapy. After finishing his training, Dr. Singh joined Radiation Oncology Associates in 2000.

“I enjoy practicing medicine in this wonderful community,” Dr. Singh said. “Being in a small community allows me more time to interact with my patients and build lasting relationships with them and their families. The medical community in this area is thriving and I am proud to be a part of a team that delivers excellent care to patients in a comfortable setting.”

Thomas A. Sheldon, MD

Concord | Radiation Treatment & Oncology

Concord

Dr. Sheldon received his Bachelor of Science degree in biochemistry from the University of Wisconsin at Madison in 1976 where he was a member of the Phi Beta Kappa honors society. While in college, he worked with a research team studying interferon. He graduated from Tufts University School of Medicine in 1980. During medical school, he participated in research in radiobiology at the Harvard School of Public Health.

Dr. Sheldon completed an internship in medicine and surgery at Newton-Wellesley Hospital in Massachusetts, where he received the Margaret Derby Scholarship award in 1981. He completed a residency in radiation oncology at the Joint Center for Radiation Therapy at Harvard Medical School in 1983. He received a National Research Service Award.

After his training, Dr. Sheldon joined the staff of the Dana Farber Cancer Institute and the New England Deaconess Hospital as an instructor in radiation therapy at Harvard Medical School, where he remained for two years. He did research and wrote extensively on locally advanced breast cancer. He also participated in pioneering work combining chemotherapy, radiation therapy and surgery in lung cancer.

Since coming to New Hampshire in 1986, Dr. Sheldon has worked extensively with the American Cancer Society, serving as the N.H. President and on the National Board of Directors. He received the St. Georges Medal, the highest honor given to volunteers. Over the years, Dr. Sheldon has worked hard to maintain his Harvard affiliation to bring academic quality care to the Merrimack Valley and Seacoast. In recent years, he and Dr. Becht established a prostate seed program, performing more than 1,000 procedures at Elliot Hospital, and more recently at Concord Hospital. With others, he developed a new radiation oncology program at Concord Hospital in partnership with the Elliot Hospital. He serves as the medical director of the Concord center.

Bryan Rowe, MD

Concord | Radiation Treatment & Oncology

Concord

Bryan Rowe studied biology at Wesleyan University, where he received his Bachelor of Arts with honors in 2000. He graduated from the University of Connecticut School of Medicine in 2007 and was granted the Excellence in Medical Studies award.
After completing his internship at Saint Vincent’s Medical Center in 2008, Dr. Rowe trained in radiation oncology at Yale New Haven Hospital, where he served as chief resident from 2011 to 2012. During residency, he gained extensive experience in the most current radiation therapy techniques, including intensity modulated radiotherapy (IMRT), image-guided radiotherapy (IGRT), stereotactic radiotherapy, and brachytherapy. Dr. Rowe also participated in a variety of research projects and published multiple articles on breast cancer and the use of stereotactic radiotherapy for lung cancer. He spent a month at the Mayo Clinic focusing on head and neck cancer and also received specialized training in prostate seed implantation at the Seattle Prostate Institute and Mount Sinai Hospital in New York City. Dr. Rowe joined Radiation Oncology Associates in 2012.

“I feel it is a great privilege to help patients and their families face the challenges of a cancer diagnosis. As part of a multidisciplinary team, I strive to provide the highest quality, individualized cancer care for patients in a comfortable, community setting.”

Vivek Patel, MD, PhD

Lowell, Nashua | Radiation Treatment & Oncology

View Dr. Patel’s Publications Below

Lowell

Nashua

Vivek Patel received his Bachelor of Science degree from Cornell University in 2006, where he was awarded honors Magna Cum Laude with Distinction in research. He further pursued his interest in biomedical science at the Weill Medical College of Cornell University, where he investigated novel drug therapies for blood disorders. He earned his M.D. and Ph.D. degrees from the Albert Einstein College of Medicine in 2007, where he achieved grant funding from the National Institutes of Health (NIH) and American Medical Association (AMA) for his work on RNA biology. Dr. Patel was elected to the Alpha Omega Alpha honor society upon his graduation from medical school in 2013.

Dr. Patel completed an internship in Internal Medicine at Mount Sinai Beth Israel Medical Center in New York in 2014. Subsequently, he relocated to Boston to train at the Harvard Radiation Oncology Program (HROP), where he treated patients at the Massachusetts General Hospital, Brigham and Women’s Hospital, Dana Farber Cancer Institute, Beth Israel Deaconess Medical Center, and Boston Children’s Hospital. Dr. Patel gained experience in treating a variety of malignancies including rare cancers of both adults and children using both photon and proton radiotherapy techniques. After the completion of his training, Dr. Patel joined Radiation Oncology Associates in 2018.

“Taking care of the men and women that make our community uniquely great is an honor and privilege that brings meaning to each day in the clinic.”

Etin-Osa Osa, MD

Burlington, Nashua | Radiation Treatment & Oncology

Burlington

Nashua

Etin-OsaOsa received her Bachelor of Science degree in Biology and Chemistry with highest academic distinction from Howard University in 2005 and earned her medical degree from New York University School of Medicine in 2009.

Dr. Osa went on to complete her internship in General Medicine and residency in Radiation Oncology at New York University (NYU) from 2009 to 2014. During her residency, Dr. Osa was involved in several clinical research projects in breast and central nervous system tumors resulting in several publications and received the New York Roentgen Society Best of ASTRO award in 2012. She served as Chief Resident from 2013-2014.

Dr. Osa has also been active in international cancer care and research. As a premedical student, she was awarded a grant from the National Institutes of Health to complete a basic science research fellowship on hepatocellular carcinoma in Hôpital Paul-Brousse in Paris, France. As a resident at NYU, she received the American Society of Radiation Oncology (ASTRO) Global Health Scholar Grant and has presented her research at several international cancer centers in various locations including Tanzania, South Africa, and Italy. As Chief Resident, she received the award for Excellence in International Cancer Outreach from NYU in 2013.

Dr. Osa joined Radiation Oncology Associates in August 2014. “I am honored to be able to provide compassionate, high quality care in a community setting. I enjoy being able to help my patients in any way possible throughout their treatment course.”

William O’Meara, MD

Lowell | Radiation Treatment & Oncology

Lowell

Bill O’Meara received his Bachelor of Arts in English from the University of Notre Dame in 1992 and completed medical training at Tulane University School of Medicine in 1997. While in medical school, he simultaneously obtained a masters degree in public health.

Dr. O’Meara completed an internship in internal medicine in 1998 at the Naval Medical Center in San Diego. From 1998-2002, he served as an active duty Naval medical officer with operational forces. He subsequently went on to specialty training and completed a residency in radiation oncology in 2006 and a fellowship in stereotactic body radiotherapy in 2007, both at Memorial Sloan-Kettering Cancer Center in New York.

After finishing training, Dr. O’Meara returned to active duty as a radiation oncologist at the National Naval Medical Center in Bethesda, Maryland, where he also served as the associate program director for the radiation oncology training program at the National Cancer Institute. Dr. O’Meara separated honorably from the Navy as a Commander and joined Radiation Oncology Associates in 2011. He has earned awards for research, teaching and excellence in patient care.

“Caring for cancer patients is a privilege. My focus with every patient is to apply the rapidly advancing technology of radiation therapy in a thoughtful, humane, and meaningful way.”

Jeffrey Brower, MD, PhD

Dover, Manchester, Portsmouth | Radiation Treatment & Oncology

Dover

Manchester

Portsmouth

Jeffrey Brower received his Bachelor of Science degree in Microbiology and Cell Science with a minor in Chemistry from the University of Florida. He then went on to earn his Ph.D. in Molecular Biology, during which time his research led to the discovery of a novel gene responsible for cellular respiration and energy metabolism. During his Ph.D. research, he was awarded the Alumni Fellowship and Medical Guild award for his work in molecular biology. Following the completion of his Ph.D., Dr. Brower matriculated to medical school at the University of Florida, graduating with research honors in 2012.

Dr. Brower completed his training in radiation oncology at the University of Wisconsin, serving as chief resident from 2016 to 2017. During residency, he gained extensive experience in the most current radiation therapy techniques, including intensity modulated radiotherapy (IMRT), Tomotherapy, image-guided radiotherapy, and stereotactic radiotherapy as well as the utilization of MRI-guided radiotherapy. In addition, Dr. Brower received comprehensive training in the utilization of brachytherapy to treat gynecologic malignancies. As a resident, Dr. Brower also participated in clinical research, publishing over 25 peer reviewed manuscripts and presenting his work at national conferences. Dr. Brower has published manuscripts on esophageal, lung, brain, head and neck, prostate, liver, skin and gynecologic cancers as well as brain metastases. After the completion of his training, Dr. Brower joined Radiation Oncology Associates in 2017. He currently serves as Gynecological Editor for Radoncquestions.com, an international online learning resource for radiation oncology physicians and trainees. Dr. Brower also is an active peer reviewer for many journals with the field of radiation oncology and continues to participate in resident education.

“It is a great privilege to care for the patients of New England. Community medicine provides me the opportunity to focus on improving the standards of patient care and ensuring that the highest quality therapy is available to patients closer to home.”

Stephen Harris, MD

Nashua | Radiation Treatment & Oncology

Nashua

Stephen Harris graduated with distinction with a degree in biomedical engineering from Purdue University in 2001. He went on to Indiana University School of Medicine in 2005 where he was a member of the Alpha Omega Alpha medical honor society. Dr. Harris stayed in Indianapolis to complete his internship at Indiana University before moving to the University of North Carolina to complete his residency in radiation oncology. While at UNC, Dr. Harris served as chief resident from 2008-2010.

During residency, Dr. Harris received extensive training on conventional external radiotherapy and IMRT as well as radiosurgery and high dose rate (HDR) brachytherapy. Dr. Harris has conducted research on young patients with head and neck cancers as well as written scholarly articles on the management of gastrointestinal cancers, radiation effects on the gastrointestinal tract, and radiosurgical treatment of liver tumors. After finishing training, Dr. Harris joined Radiation Oncology Associates in 2010.

“I chose to pursue a career in radiation oncology because it allows me an opportunity to apply my technical abilities and interests to the care of patients. I am deeply fascinated and, at the same time, humbled by the field of oncology. I consider it a great honor to take part in the lives of cancer patients and enjoy working with teams of talented and caring practitioners to better serve my patients.”

Howard Hsu, MD

Burlington, Peabody | Radiation Treatment & Oncology

View Dr. Hsu’s Publications Below

Burlington

Peabody

Howard Hsu received his Bachelor of Science degree in Bioengineering from the University of California Berkeley in 1998. He served as a Peace Corps Volunteer in a rural village of South Africa from 1999-2001, working on education and community health projects. He earned his medical degree from Cornell University Medical College in 2005.

Dr. Hsu served for three years as an intern and resident in General Surgery at Washington University / Barnes-Jewish Hospital from 2005-2008. He subsequently pursued research training in radiation biology at the University of California San Francisco / Lawrence Berkeley National Laboratory.

Dr. Hsu trained in Radiation Oncology at New York University from March 2010 to February 2014. During his residency training, he developed a research interest in comparative effectiveness and health-related quality of life. He served as Chief Resident from 2012-2013. Dr. Hsu joined Radiation Oncology Associates in March 2014.

“It is an honor and privilege to serve my patients. I am committed to providing the highest level of care, with special attention to maintaining my patients’ quality of life.”

Klaudia Hunter, MD

Burlington, Lowell | Radiation Treatment & Oncology

Burlington

Lowell

Klaudia Hunter received Bachelor Degrees with Distinction in both philosophy and biology from the University of Illinois at Chicago in 2001. She then graduated with honors from the University of Illinois Medical School in 2006 after completing the James Scholar Program for Independent Study and playing a leadership role in the Alpha Omega Honors Society.

Dr. Hunter completed her surgical internship at the University of California at San Diego in 2007. She continued in the neurosurgical residency training program at the University of California at San Diego until June 2009 when she chose to leave to pursue a career in radiation oncology. She trained in radiation oncology at the University of Michigan from July 2009 to June 2013 and served as chief resident from April 2012 to April 2013. During her residency, she was also the recipient of the Woodworth Resident Research Award and the RSNA Roentgen Resident Research Award. During this time, she developed expertise in the use of intensity modulated radiation therapy (IMRT) for treating complex head and neck cancers and stereotactic treatments (SRS and SBRT) for the treatment of intracranial and extracranial disease. In May 2013, Dr. Hunter received the American Brachytherapy Society HDR Fellowship to receive additional training in brachytherapy for gynecologic, breast, and prostate cancers.

After finishing her training, Dr. Hunter joined Radiation Oncology Associates in August 2013.

“I love interacting with patients and feel privileged to be able to help them through their cancer journey. My most important job is to make patients feel cared for and listened to.”

Matthew S. Katz, MD

Lowell, Manchester | Radiation Treatment & Oncology

Lowell

Manchester

Matt Katz received his Bachelor of Arts degree in history from Northwestern University in 1992 and graduated from the University of Massachusetts Medical School in 1998. During medical school, he also completed a fellowship in pathology.

Dr. Katz completed an internal medicine internship at Evanston Hospital in 1999. He completed his radiation oncology residency at Memorial Sloan-Kettering Cancer Center in 2003. During internship and residency, he received several awards for patient care and research. He developed expertise in the use of newer technologies such as intensity modulated radiation therapy (IMRT) to improve the accuracy and safety of radiation therapy. From 2003-2004, Dr. Katz was on staff at the Massachusetts General Hospital in the Department of Radiation Oncology, where he specialized in breast cancer and remained involved in teaching and research at Harvard Medical School until 2009.

Since joining Radiation Oncology Associates, he was worked in both New Hampshire and Massachusetts. He served as Director of the Department of Radiation Oncology at Saints Medical Center and Lowell General Hospital 2007-2018. He remains involved in clinical research with interests in cancer care and patient-doctor communication, serving as Chair of Communications for the American Society for Radiation Oncology (ASTRO) and the Massachusetts Medical Society. However, direct patient care remains the core focus of his work.

“Community medicine offers me the opportunity to spend more time with my patients and to make quality cancer care available closer to home. It is a privilege to help my patients and their loved ones with the medical and personal challenges of a cancer diagnosis.”

Brian R. Knab, MD

Londonderry, Manchester | Radiation Treatment & Oncology

Londonderry

Manchester

Brian Knab received a Bachelor of Arts degree in interdisciplinary studies at the University of Virginia in 1997. He graduated from Duke University Medical School in 2002 as a member of the Alpha Omega Alpha medical honor society. While in medical school, he participated in a year-long laboratory research program at the University of California at San Francisco investigating new cancer treatments.

Following medical school, Dr. Knab returned to the University of Virginia to complete an internship in internal medicine. He continued his training in radiation oncology at the University of Chicago Medical Center and served as chief resident from 2005 to 2006. During residency, Dr. Knab received extensive training in the latest radiation therapy techniques including intensity modulated radiotherapy (IMRT), stereotactic radiotherapy, and brachytherapy. Dr. Knab also received additional clinical training at the Royal Marsden cancer hospital in London, England and the Seattle Prostate Institute. During residency, Dr. Knab participated in clinical research investigating the treatment of gastrointestinal and gynecologic cancers, brain tumors, and head and neck cancers. He also performed laboratory research in tumor immunotherapy and radiobiology.

“Cancer treatment is a rapidly advancing medical field and it is exciting to be a part of this ongoing revolution,” Dr. Knab said. “I strive to incorporate the latest advancements and technologies into my medical practice to offer the optimal treatment for each individual. I feel privileged to work in this wonderful community with such talented professionals to help provide state of the art cancer care in a compassionate and caring environment.”

Jeffrey Lemons, MD, MS

Dover, Peabody, Portsmouth | Radiation Treatment & Oncology

Dover

Peabody

Portsmouth

Jeff Lemons earned his Bachelor of Science degree from the University of Michigan in Ann Arbor, MI with a major in Cellular, Molecular, and Developmental Biology and a minor in Spanish. After finishing at Michigan, he was selected for the Intramural Research Training Award through the NIH and participated in a year-long research program at the NIDDK in Bethesda, MD. Afterwards, he matriculated into medical school at Temple University School of Medicine in Philadelphia, PA and graduated in 2013 as a member of the Alpha Omega Alpha Honor Society.

After medical school, Dr. Lemons completed internship at Crozer Chester Medical Center in Upland, PA followed by radiation oncology residency at the University of Chicago where he served as Chief Resident in his final year. During his training, he performed clinical research focusing on combining stereotactic body radiotherapy (SBRT) and immunotherapies as well as the utilization of radiation for oligometastases. Dr. Lemons has presented research at national meetings, published in peer-reviewed journals, and authored and managed clinical trials. To expand the scope of his training, he completed externships at the Northwestern Medicine Chicago Proton Center and The Royal Marsden Hospital in London, England. He attended the ASCO/AACR Methods in Clinical Cancer Research Workshop and earned a Master of Science through the Department of Public Health Sciences while at the University of Chicago.

Dr. Lemons joined Radiation Oncology Associates in 2018 after completing his training. He finds great satisfaction working with a team to provide high-quality and individualized care for his patients and help guide them through a difficult time in their lives.

Arul Mahadevan, MD

Dover, Portsmouth | Radiation Treatment & Oncology

Dover

Portsmouth

Arul Mahadevan received his Bachelor of Medicine and Surgery from the University of Madras (Chennai) in 1987 and received his Master of Surgery in Orthopedics from the University of Bombay in 1991. After being awarded Fellowships of the Royal Colleges of Surgeons of Edinburgh and Glasgow, United Kingdom, Dr. Mahadevan moved to the United States to practice medicine.

His interest in cancer care led him to complete residency in radiation oncology at Northwestern University, where he served as chief resident. He has completed advanced fellowship training in brachytherapy at Beth Israel Medical Center in New York and a prostate cancer brachytherapy fellowship at the Seattle Prostate Institute before joining the Cleveland Clinic as an Assistant Professor in Radiation Oncology in 2002.

While at the Cleveland Clinic, Dr. Mahadevan specialized in treating genitourinary malignancies including prostate brachytherapy and image guided radiation therapy (IGRT) and published extensively. He was also the director of clinical research at the Cleveland Clinic Cancer Center. He has an active leadership role in national cancer trials and served as Co-Director of the first International Symposium on Stereotactic Body Radiation Therapy and Stereotactic Radiosurgery.

Since joining Radiation Oncology Associates in 2008, Dr. Mahadevan has further helped us make new radiation technologies available usually only available at major academic centers. He continues to remain active in clinical trials with RTOG and serves on the Government Relations Committee and Education Committee for the American Society of Radiation Oncology. He is also the Medical Director of the Radiation Therapy Training Program of the New Hampshire Technical Institute.

Andrea B. McKee, MD

Burlington, Peabody | Radiation Treatment & Oncology

Burlington

Peabody

Andrea McKee received her Bachelor of Arts degree in biology in 1992 from the University of Pennsylvania with honors. She graduated from Columbia University College of Physicians and Surgeons in 1996. During college and medical school, she participated in laboratory and clinical research prior to continuing with her clinical training.

Dr. McKee stayed in New York City for her internship in internal medicine at Lenox Hill Hospital. She continued her training in radiation oncology at Memorial Sloan-Kettering Cancer Center, where she was named Chief Resident for 2000-2001.

During residency, Dr. McKee researched clinical outcomes in patients with tumors of the prostate, uterus, cervix, and musculoskeletal system. She developed expertise in intensity modulated radiation therapy (IMRT), high dose rate (HDR) brachytherapy and stereotactic radiosurgery. After finishing her training at Memorial Sloan-Kettering Cancer Center, Dr. McKee joined Radiation Oncology Associates in 2001.

Dr. McKee helped establish an HDR brachytherapy program in southern New Hampshire in 2004. With a team of neurosurgeons, oncologists, physicists, radiation therapists and oncology nurses, she developed a stereotactic radiotherapy program at the Elliot Hospital where she served as the medical director and co-director of the Elliot Radiosurgery Center. She now serves as the Chair of the Department of Radiation Oncology at Lahey Clinic in Burlington and Peabody.

“I became a radiation oncologist in order to practice medicine in an area that challenged me both emotionally and intellectually. The technological and therapeutic advances in radiation and medical oncology seen over the past few years have led to impressive and meaningful improvements in overall survival and quality of life for our patients. It is an exciting time for those of us who share in the privilege of caring for patients with cancer.

Su Metcalfe, MD, MPH

Concord, Londonderry | Radiation Treatment & Oncology

Concord

Londonderry

Su Metcalfe received her Bachelor of Arts in Asian Studies from Pomona College in 1996. Following this, she received a Masters of Science in Biology with a focus in Immunology from NYU in 1999 and completed a research fellowship at the National Institutes of Health. She earned a Masters of Public Health degree from Columbia University in 2001. In 2005, she graduated from the University of Vermont College of Medicine.

After her internship in internal medicine at Beth Israel Deaconess Medical Center in Boston, Massachusetts, Dr. Metcalfe completed her radiation oncology training at the University of Rochester Medical Center in 2010. During her residency, she received training in stereotactic radiosurgery, image-guided radiotherapy, and intensity modulated radiation therapy. She participated in clinical research utilizing these techniques, specifically in the treatment of metastatic disease. She also performed laboratory research investigating the role of radiation in inducing tumor-specific immunologic response. Dr. Metcalfe has earned awards for research and excellence in patient care. She joined Radiation Oncology Associates in 2010.

Asa J. Nixon, MD, MPH

Burlington, Peabody | Radiation Treatment & Oncology

Burlington

Peabody

Asa Nixon received his Bachelor of Arts degree from Dartmouth College in 1984. In 1988, he graduated with his medical degree from New York University School of Medicine.

Dr. Nixon completed two years of residency in general surgery at New England Deaconess Hospital in Boston, MA. He continued his training in radiation oncology at the Joint Center for Radiation Therapy (JCRT), Harvard Medical School. During residency, Dr. Nixon completed a fellowship in cancer epidemiology from the Harvard School of Public Health, receiving a Masters in Public Health degree.

After finishing his training, Dr. Nixon joined the medical staff at Beth Israel Deaconess Medical Center, the Dana-Farber Cancer Institute and the JCRT where he was an Assistant Professor of Radiation Oncology at Harvard Medical School and specialized in the treatment of breast cancer and tumors of the head and neck.

Since he joined Radiation Oncology Associates in 1999, Dr. Nixon has worked at our New Hampshire sites in Manchester, Dover and Exeter. He currently works full-time at the Lahey Hospital in Burlington Massachusetts where his clinical interests include lung cancer, brain tumors, breast cancer and colorectal malignancies.